I laughed when I read the comments by MikeStheplumber. I've sold over 200 of these Takagi water heaters in the last 9 months...all sizes, T-K Jr., T-K2, T-KD20 and T-M1s. The only problems I ever hear about are when Plumbers install them. The homeowners seem to have a real grasp on the whole concept. I haven't heard a bad word from any of my Customers, have not had a single return. I think the Plumbing industry has a hard time grasping this new technology. The Takagi units are awesome. These water heaters are the future folks. They've been used in Europe for over 150 years in addition to other parts of the world. Can all of these people be so wrong for so long?